SAN DIEGO -- As a swarm of reporters approached Padres first baseman Yonder Alonso prior to Friday's game against the Giants, shortstop Everth Cabrera stood by him pretending to be his bodyguard.
Cabrera likely didn't want anything to happen to Alonso, who returned Friday from the disabled list after missing 34 games with a broken bone in his right hand. He was in the lineup along with second baseman Jedd Gyorko, who was playing for the first time since June 10 after straining his right groin. The two combined have hit .332 with eight homers and 29 RBIs at home this season.
However, neither their return nor a sellout crowd at Petco Park could spark the Padres on Friday as they were shellacked by the Giants, 10-1.
Arguably the worst loss of the season for the Padres got away from them in the seventh inning when the Giants sent 10 batters to the plate and scored five runs, although Padres manager Bud Black wasn't around to see the end of it.
He was ejected with two outs in the inning by second-base umpire Laz Diaz for arguing an obstruction call. The Giants' Kensuke Tanaka collided with Padres third baseman Chase Headley while trying to avoid the tag in a rundown, but was awarded third base.
According to baseball's Rule 7.08, a runner's baseline is established when the tag attempt occurs and is a straight line from the runner to the base he is attempting to reach safely.
It was the second time this season that Black has been thrown out of a game.
If Tanaka had been called out, the Padres would have gotten out of the inning with limited damage. Instead, the Giants (42-50) proceeded to tack on four unearned runs off reliever Brad Brach to make it 10-1 and put the game all but out of reach.
The Padres have now lost 13 of the past 14 games and 17 of their last 20.
"You've got to weather the storm and come in each day with the expectation that you're going to win," Black said. "We've got to get that big hit, make the big pitch."
The Padres actually scored first Friday on an RBI double by Headley in the first inning, his sixth extra-base hit in the month of July, after only having five in all of June.
Turns out, that was all they would muster off Giants starter Chad Gaudin (3-1), who surrendered three hits and four walks in five-plus innings but held the Padres to one run.
San Diego native Sean O'Sullivan made his first career start for the Padres. He called the chance to pitch for the team he grew up rooting for a dream come true earlier this week and began his night with a 1-2-3 first inning, then doubled off the wall in the third inning.
"I tried to soak up as much as I could," O'Sullivan said. "Especially walking from the 'pen to the dugout trying to take it all in. It was exciting. Lot of nerves, lot of adrenaline, so that was tough to calm down to go out there and pitch."
O'Sullivan flirted with trouble too often, allowing multiple baserunners in each inning after the first and running up his pitch count to 102. The Giants could only push across runs in the third and fifth innings, on a sacrifice fly by Buster Posey and an RBI double by Pablo Sandoval, but it did give them a 2-1 lead.
O'Sullivan (0-1) allowed two runs on six hits and three walks in five innings.
"I thought Sean battled," Black said. "They put some stress on him. He competed great. He pitched with a lot of emotion."
The Giants began to break the game open with a three-run sixth highlighted by a two-run single from Posey. San Francisco had struggled recently on offense but tied a season high with 17 hits.
The Padres loaded the bases with no outs in the sixth, forcing Gaudin from the game, but failed to score off reliever Jose Mijares, who needed eight pitches to get Alonso to pop out before he proceeded to strike out Gyorko and a pinch-hitting Chris Denorfia.
"I was ready for anything," Mijares said.
Then the Giants blew the game out of reach and dropped the Padres (41-53) to a season-worst 12 games under .500.
Jamal Collier is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.